CAM OVER

[bozo699]

Boyd saw the air gap above and said sizing being a bit more complex that it might seem to be at first glance.

The Redding competition shell holders allows you to make hard contact between the die and shell holder with no air gap. This takes the slop out of the press linkage, compensates for different brands of cases and their hardness. And makes the case shoulders more uniform after sizing.

If you use the same brand of brass and anneal every time then maybe your press and sizing method do not require competition shell holders.

P.S. bozo699 for agreeing with Dusty may the fleas of a thousand camels infest your crotch.

Ed,
I may have to agree with Dusty more often lol
Happy Bumping buddy

 

[ronsatspokane]

I think he’s trying to say that fireforming uses brass with huge clearances, as if the brass was grossly over-sized in a die. Yet fireformers can shoot very well at times.

My answer to that is: fireforming 6BRA involves brass that is still very well aligned by the fit at the neck/shoulder junction and/or the bullet jammed in the throat. So yes it’s not surprising it can shoot. Velocity might not be reliable but in short range there are plenty of shooters who shoot fireformers in fun matches.

David

Yes, that is what I'm saying. As far as velocity, I had the Labradar running and the SD and ES numbers were pretty darn good. SD in the single digits.

 

[Metal God]

I think the confusion is with the term cam over because some presses don't even allow for that . IMHO the term that should be used is firm contact between die and shell holder . This would result in cam over with presses that allow for it and is self explanatory for those that don't .

All presses will have some flex/stretch/deflection when sizing a case , some more then others . I find that deflection seems to be more in the linkage between the ram and handle rather then the frame of the actual press .

Here is how much my Hornady press deflects when sizing a 308 case . You must look for the gap/crack of light when sizing a case , not with a empty die and ram fully up .

No case in the die with die and shell holder just kissing notice no gap .

Now when sizing a LC 308 case with the die at the same adjustment as above , the gap/space appears

This is do to that press flex/deflection . The best way to defeat press deflection is for the die and shell holder to make firm contact . When doing that with a standard shell holder the case gets sized to SAAMI minimum or smaller . The problem most of use run into with that is we often don't want are cases sized down that far and we need to back are die out to get the proper shoulder bump . How ever as soon as the die is no longer making contact with shell holder we introduce that press deflection back into the sizing process .

Depending on the case and or how work hardened it is . If your die and shell holder are not making firm contact . The cases can come out longer or shorter ( head to datum ) do to how much the press deflects on each individual case . When we're only talking .002 of movement needed in most cases the press does not need to give much for it to translate to the sized case .

So if a standard shell holder when making firm contact with the die sizes your case to 1.618 and you want it sized to 1.624 . How can you get that 1.624 bump with out adjusting the die out introducing that flex ? That's when the Redding competition shell holders come in . They come in a set of five and allow you to size your cases longer then a standard shell holder while still making firm contact with the die . They allow you to size your cases longer ( from head to datum ) in .002 increments from a standard shell holder . Those increments are marked on each shell holder in the set . When used as designed the consistency in which I can size my cases is still a little mind blowing to me . Most of my cases regardless of manufacturer or times fired ( up to 4 because I anneal after forth firing ) come out +/- .0005 . some cases come out +/- .001 but not many .

IMO , one of the best things the competition shell holders allow me to do or in this case NOT to do is never needing to adjust my sizing die/s in the press . I load for multiple 308's and multi multiple 223/5.56

. All four 308's are sized different and three of the AR's are sized different . I size on a single stage press and haven't adjusted my die/s in years to size for any of those rifles regardless of how far I bump the shoulders .

If rifle A needs a shoulder bump to 1.626 and rifle B needs a shoulder bump to 1.622 . you just use the proper Redding competition shell holder which gives you the bump you need with out having to adjust the die . While always putting a higher load on the press then sizing does which removes all press flex/deflection issues .

 

[dgeesaman]

Yes, that is what I'm saying. As far as velocity, I had the Labradar running and the SD and ES numbers were pretty darn good. SD in the single digits.

Interesting. I was getting good fireforming accuracy from my last 6BRA barrel but once I got to 100 rounds I stopped running empty rounds through it.

In any case, the reason why this can’t be done repeatedly is the brass won’t hold up. Plus the interference at the neck-shoulder junction is gone when you resize and bump the shoulder.

David

 

[fatelvis]

I think the confusion is with the term cam over because some presses don't even allow for that . IMHO the term that should be used is firm contact between die and shell holder . This would result in cam over with presses that allow for it and is self explanatory for those that don't .

All presses will have some flex/stretch/deflection when sizing a case , some more then others . I find that deflection seems to be more in the linkage between the ram and handle rather then the frame of the actual press .

Here is how much my Hornady press deflects when sizing a 308 case . You must look for the gap/crack of light when sizing a case , not with a empty die and ram fully up .

No case in the die with die and shell holder just kissing notice no gap .

Now when sizing a LC 308 case with the die at the same adjustment as above , the gap/space appears

This is do to that press flex/deflection . The best way to defeat press deflection is for the die and shell holder to make firm contact . When doing that with a standard shell holder the case gets sized to SAAMI minimum or smaller . The problem most of use run into with that is we often don't want are cases sized down that far and we need to back are die out to get the proper shoulder bump . How ever as soon as the die is no longer making contact with shell holder we introduce that press deflection back into the sizing process .

Depending on the case and or how work hardened it is . If your die and shell holder are not making firm contact . The cases can come out longer or shorter ( head to datum ) do to how much the press deflects on each individual case . When we're only talking .002 of movement needed in most cases the press does not need to give much for it to translate to the sized case .

So if a standard shell holder when making firm contact with the die sizes your case to 1.618 and you want it sized to 1.624 . How can you get that 1.624 bump with out adjusting the die out introducing that flex ? That's when the Redding competition shell holders come in . They come in a set of five and allow you to size your cases longer then a standard shell holder while still making firm contact with the die . They allow you to size your cases longer ( from head to datum ) in .002 increments from a standard shell holder . Those increments are marked on each shell holder in the set . When used as designed the consistency in which I can size my cases is still a little mind blowing to me . Most of my cases regardless of manufacturer or times fired ( up to 4 because I anneal after forth firing ) come out +/- .0005 . some cases come out +/- .001 but not many .

IMO , one of the best things the competition shell holders allow me to do or in this case NOT to do is never needing to adjust my sizing die/s in the press . I load for multiple 308's and multi multiple 223/5.56

. All four 308's are sized different and three of the AR's are sized different . I size on a single stage press and haven't adjusted my die/s in years to size for any of those rifles regardless of how far I bump the shoulders .

If rifle A needs a shoulder bump to 1.626 and rifle B needs a shoulder bump to 1.622 . you just use the proper Redding competition shell holder which gives you the bump you need with out having to adjust the die . While always putting a higher load on the press then sizing does which removes all press flex/deflection issues .

Excellent job of wording what I was thinking! Lol
I love the competition shell holder sets. They save me time, and let you set up for different rifles consistently.

 

[Uncle Ed]

Below is a link to 14 presses being tested and it measures the flex and slop in the "NEW" presses. On the second page it has a chart with data summaries and the base to shoulder variations. And the worst press had .0015572 average shoulder variations.

Fourteen Reloading Presses Compared: Single-Stage Shootout
https://ultimatereloader.com/2019/04/08/fourteen-reloading-presses-compared-single-stage-shootout/

The chart below tells you if the press cams over or reaches a hard stop. (click on both images to enlarge)

And this chart shows base to shoulder variations in shoulder bump.

 

[Metal God]

.0015 is huge when you’re only try to get that same amount of bump and tracks pretty much exactly with my experience. Interesting that the press that has the worst results base to shoulder ( case headspace ) is the same press I’m using , I wonder if the bushing system has anything to do with it . I always felt the Hornady press was one of the worst on the market but never had another press to compare to . Before I started using the comp shell holders and I was only trying to bump the shoulders .002 . Some cases didn’t seem to bump at all while others would bump more . It was mostly they didn’t bump at all which is what lead me to conclude the flex in the press was the issue .

 

[bozo699]

Below is a link to 14 presses being tested and it measures the flex and slop in the "NEW" presses. On the second page it has a chart with data summaries and the base to shoulder variations. And the worst press had .0015572 average shoulder variations.

Fourteen Reloading Presses Compared: Single-Stage Shootout
https://ultimatereloader.com/2019/04/08/fourteen-reloading-presses-compared-single-stage-shootout/

The chart below tells you if the press cams over or reaches a hard stop. (click on both images to enlarge)

And this chart shows base to shoulder variations in shoulder bump.

Ed,
Thank you for posting press charts I’ve looked for this many times
Wayne

 

[Uncle Ed]

My Rockchucker press is 47 years old and the linkage and pivot pins are worn and the press does have slop.

And this is where the Redding competition shell holders come into play. If the die is making hard contact with the shell holder with press cam over this eliminates any press slop. Meaning far less variations in shoulder bump and pausing at the top of the ram stroke makes the shoulder even more uniform.

The only exception to this that I know of is full length resizing Lake City 7.62 cases that were fired in a machine gun. And these cases need to be sized more than once and beaten into submission. (Subliminal suggestion) Do not even think about sizing these type Lake City cases with Hornady One Shot. You might rip your shoulder out of its socket and end up with a case stuck in the die.

A carbide .45 ACP die or a 30-06 die can be used to size these cases first followed by sizing in a small base die.
And remember cheap bastards have more fun regardless of how much their right arm hurts.

 

[K22]

Before the Redding competition shell holder were made by them you adjusted the die for bump with feeler gauges.

The problem with this method is the air gap between the die and shell holder and not eliminating any flex in the press. And Skips shims raise the die above the shell holder and add to any press flex problems.

And Redding, RCBS and Forster dies instructions tell you to turn the die 1/8 to 1/4 past contact with the shell holder.

And we have talked about pausing at the top of the ram stroke to get more uniform shoulder bump. And if the press has any flex you need to have the die make hard contact with the shell holder.

I do obtain consistent shoulder set back using Skip Shims for my bolt rifles. I measure with Whidden Gun Works bump gauges and a dial caliper. Cases are dedicated to a specific rifle.

I set up the die so the shell holder makes firm contact with the die by using the middle Skim, i.e. .005 then adjusting the amount of sizing using the .003, .004, .006, .007, 008, or .010. to increase or decrease the amount of shoulder set back as needed. Seems to work but maybe I'm missing something here.

 

[bozo699]

I reread this whole thread!.... this press that press this die that die!..cam over no cam over shims!... competition shell holders!... shaving off shell holder” I have had to do that” and on and on and on about getting consistent shoulder bump!... I use 4 primary presses
Redding T7 , Rockchucker, Harrells and a cheap small aluminum framed rcbs and occasionally a Lee hand press and I have no problems keeping my shoulders around .001 setback on my brx and .002 on my hunting rifles! I can achieve that with out any magic shell holders or expensive presses!...

#1 A clean die properly adjusted
#2 clean cases
#3 anneal every time “or not at all”
# 4 and probably the most important
Properly and consistently proper case lubing!..
Same cycle time on the press weather your fast cycle or a 5 minute dwell do it the same!..

and wala consistent shoulder bump!

I’ve seen people over lube under lube lube every other case ..... you CANNOT do that and have consistent shoulder bump!

Happy Bumping my friends!
Wayne

 

[Ralph Littlefield]

.........I’ve seen people over lube under lube lube every other case ..... you CANNOT do that and have consistent shoulder bump!

Happy Bumping my friends!
Wayne

I think this is very good advise. I would add that lubing inside the case neck is an important part of the process.

On lube brand, I tried some Imperial wax, and while I liked the process better, the results were not a good as with RCBS lube 2. Cases enter the die with much less pressure with the RCBS lube.

 

[danny]

In the "Peak Sizing Force" column, the lower numbers are better? That is, they are measuring the force required on the handle for resizing and not the final force developed by the press? My Lee Classic Cast always seems to resize cases much more easily than my Forster Co-Ax, which seems odd, by the data, if I read it correctly.

Danny

Below is a link to 14 presses being tested and it measures the flex and slop in the "NEW" presses. On the second page it has a chart with data summaries and the base to shoulder variations. And the worst press had .0015572 average shoulder variations.

Fourteen Reloading Presses Compared: Single-Stage Shootout
https://ultimatereloader.com/2019/04/08/fourteen-reloading-presses-compared-single-stage-shootout/

The chart below tells you if the press cams over or reaches a hard stop. (click on both images to enlarge)

And this chart shows base to shoulder variations in shoulder bump.

 

[Uncle Ed]

Happy Bumping my friends!
Wayne

Bozo699 why did you end this with "Happy Bumping" when we have so much spare time on our hands to argue about it.

I guess happy bumping from bozo699 is better than F. Guffey inventing datums and his magic feeler gauges.

"BUT" the "Bump Wars" are not over by a long shot, no matter what bozo699 tells us.

 

[ronsatspokane]

Interesting. I was getting good fireforming accuracy from my last 6BRA barrel but once I got to 100 rounds I stopped running empty rounds through it.

In any case, the reason why this can’t be done repeatedly is the brass won’t hold up. Plus the interference at the neck-shoulder junction is gone when you resize and bump the shoulder.

David

I agree. Brass would not last long at all. My question though is more along the lines of is sizing really adding what people think it is. Neck turning and neck tension seem to have a clear impact on accuracy but if the shoulder is knocked back two thousands or ten thousands, does it really make a difference? Especially considering that the body is also sized while the shoulder is being knocked back.

 

[J.d. Popkes]

I agree. Brass would not last long at all. My question though is more along the lines of is sizing really adding what people think it is. Neck turning and neck tension seem to have a clear impact on accuracy but if the shoulder is knocked back two thousands or ten thousands, does it really make a difference? Especially considering that the body is also sized while the shoulder is being knocked back.

In my experience, limited as it is, consistent sizing/bump is important. I think minimum bump is easy on brass but if every piece is bumped .006 it’s probably gonna be alright especially if you seat in the lands. I had a well renowned shooter explain to me that they want the case basically floated. Touching on the case head/bolt face and the lands. Small base sized each time. Kinda between centers if ya will.

all I know for sure is, if I don’t do what I gotta do to get consistent sizing I can see it on paper and on the magnetospeed. However a guy gets consistent sizing, well, who cares right.

 

[M-61]

I guess happy bumping from bozo699 is better than F. Guffey inventing datums and his magic feeler gauges.

F Guffey was in a class all by himself. With time on my hands I miss his posts.
"Bumping" (or the fact that you can not) let him run wild. For me Guffey made for some really interesting yet totally uninformative reading. His search for datums....his 'only I know' information.........his unique measuring systems...Beat the hell out of " How to clean a Barrel" posts..
However I do hope he is OK in whatever galaxy he traveled to.

 

[ronsatspokane]

In my experience, limited as it is, consistent sizing/bump is important. I think minimum bump is easy on brass but if every piece is bumped .006 it’s probably gonna be alright especially if you seat in the lands. I had a well renowned shooter explain to me that they want the case basically floated. Touching on the case head/bolt face and the lands. Small base sized each time. Kinda between centers if ya will.

all I know for sure is, if I don’t do what I gotta do to get consistent sizing I can see it on paper and on the magnetospeed. However a guy gets consistent sizing, well, who cares right.

I don't usually full length size until the brass starts getting "tight" in the chamber. Like every 5th firing. I neck size only and only shoot that brass in one chamber. Not sure I'm buying myself anything especially given the experience with this 6BRA.

 

[JFrank]

F Guffey was in a class all by himself. With time on my hands I miss his posts.
"Bumping" (or the fact that you can not) let him run wild. For me Guffey made for some really interesting yet totally uninformative reading. His search for datums....his 'only I know' information.........his unique measuring systems...Beat the hell out of " How to clean a Barrel" posts..
However I do hope he is OK in whatever galaxy he traveled to.

Mr. Guffey was doing well a couple months ago on the high road forum.

 

[K22]

I reread this whole thread!.... this press that press this die that die!..cam over no cam over shims!... competition shell holders!... shaving off shell holder” I have had to do that” and on and on and on about getting consistent shoulder bump!... I use 4 primary presses
Redding T7 , Rockchucker, Harrells and a cheap small aluminum framed rcbs and occasionally a Lee hand press and I have no problems keeping my shoulders around .001 setback on my brx and .002 on my hunting rifles! I can achieve that with out any magic shell holders or expensive presses!...

#1 A clean die properly adjusted
#2 clean cases
#3 anneal every time “or not at all”
# 4 and probably the most important
Properly and consistently proper case lubing!..
Same cycle time on the press weather your fast cycle or a 5 minute dwell do it the same!..

and wala consistent shoulder bump!

I’ve seen people over lube under lube lube every other case ..... you CANNOT do that and have consistent shoulder bump!

Happy Bumping my friends!
Wayne

Yea, that would work for a one die setting / one rifle / group of cases dedicated to that rifle which is precisely what I do for my 308 Remington. I may only have to change the die setting as the cases age or if I retire the old cases and start with another lot.

However when I load for multiple rifles of the same caliber I need a system to make easy die adjustments. For example, I have a 243 Browning, 243 Tikka, and a 243 Rem Model 7 with a custom Hart barrel. These rifles require a different die setting to achieve a .001 to .002" shoulder set back.

Rather readjusting the die each time I reload for a different rifle, I have my 243 Full Size die set to make contact with the shell holder using a 006" shim. All I have to do is change shims to achieve the desire set back. For example, the 243 Browning needs a .004" shim, the Tikka a .003" shim, the Model 7, a 008" shim. Also as cases age or if I retire a set cases and start with a new lot of cases I can easily adjust the amount sizing the appropriate amount to achieve the desired set back.